Adjustable dowel pin



Sept. 8, 1953 A. H. LE FEBVRE ET AL 2,651,453

ADJUSTABLE DowEL PIN Filed May 20, 1949 s cu L rc f \s n J J l E 2 f j l I N5 l Q A l l a 2 \4\\ I e T' :ge/f: H

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co' 3 ul /A/VfA/TRS ARTHUR H. LEFEBVRE DAV/D E. D. SM/TH ay /`l v Patented Sept. 8, 1953 ADJUSTABLE DOWEL PIN Arthury H. Le Febvre, Washington Township, Bergen County, and David E. D. Smith, Newark, N. J., assignors tov Bendix Aviation Corporation, Teterboro, N. J.,` a corporation of Delaware.

Application May 20, 1949, Serial No..94,408

In an air pump, for example, it is particularlydesired to control the clearance between the pump rotor and the pump cylinder, this dimension being critical because leakage in the pump generally occurs therethrough with the resulting drop in pump performance and eliiciency.

Heretofore, in adjusting a clearance between the rotor of a pump and the pump barrel, the expedient usually employed was a system of trial and error whereby the pump was assembled with a selected clearance between the aforenoted parts, and thereafter, trial runs ofthe pump were performed. In the event that the selected clearance proved unsatisfactory, it was neces sary to disease the rotor to select another clearance and then reassemble the pump for another trial run. This procedure was repeated as many times as necessary until a satisfactory clearance was hit upon, at which the leakage of the pump with respect to performance was minimum.

It is, therefore, one of the objects of the present invention to overcome the aforenoted problems, and to do so by novel and effective means.

Another object of the invention is to provide anA adjustable type of dowel pin useful to regulate the clearance between the pump rotor and the pump barrel in assembling an air pump.

Another object of the invention is to provide a novel type of dowel pin adaptedto adjust the alignment between mating parts.

Still another object of the invention svto `pro-- vide a novel type of dowel pin whereby the clearance between the rotor and the barrel of .an air pump may be adjusted with the pump assembled.

Still another object of `the invention is to 'provide a new type of dowel pin which will be easy and economical to manufacture and exceedingly simple to install.

The foregoing and other objects and advantages will appear more fully hereinafter from a consideration of the detailed description which follows, taken together with the accompanying drawings, wherein one embodiment of the inven- 3 Claims. `(Cl. 5230-151) tion is illustrated by way of example. It is to be expressly understood, however, that the drawing is for the purposes of illustration only, and is not to be construed as defining the limits of. the invention, reference being` had for this purpose to the appended claims.

Referring to the drawing wherein like ref-v erence characters designate like parts:

' Figure 1 is a sectional View of an air pump showing the adjustable dowel pin installed.

Figure 2 is a detail of the adjustablev dowel pm. A

Referring now to the drawing, and more particularly to Figure 1, an air pump of the typev well. known to the art, generally indicated by the arrow I0, has a barrel I2- with fianges I4 and I-6 on each end thereof adapted to be bolted to anges IB and Zorrespectively of the back head, or end member, 22 and the mounting head, or end member, 24 of the pump I0.

Bearings 28 and 3B are positioned in the back head 22 and mounting head 24, and support the pump rotor 32 which is connected to the external drive shaft 34.

The rotor 32 clears the inner surface of the. barrel I0 by a distance designated as A.

Referring now to Figure 2, the adjustable dowel pin 36 contains a cylindrical portion 38. and a tapered conical portion Il@ and a threadedstem 42.l

A hexagonal recess 44 adapted to receive a Wrench or similar tool is contained in the stem 42. The center line of the cylindrical portion 38y is off-set a distance B yfrom the center line of the tapered portion and threaded portion, for reasons hereinafter explained.

Referring back to Figure 1, a hole, or seat, 46 in the flange I4 of the same diameter as the portion 38 of the dowel pin, lines up with hole, or seat,r 43, in the liange IB, which is tapered to match the tapered portion of the dowel pin 36.

It willV now be apparent to those skilled in the art that in assembling the pump, when the dowel pin 36 is installed in hole 46 andsnugly into the tapered hole, it will 4maintain the lrelationship between the barrel ,l2 and the back head 2,2. However, due to the eccentricity designated by dimension B between the tapered section 40 and the cylindrical section 38 of the pin, upon rotating the pin, the back head 22 will be moved with respect to the barrel l2. This movement will include the rotor 32, which is supported by bearing 28 in the back head 22. Therefore, the clearance A between the rotor 32 and the inner surface of the barrel l2 will change. Said change in clearance will be reflected by the frictional resistance encountered upon turning the drive shaft 34. Thus, by simultaneously rotating the dowel pin 36 and the shaft 34, the correct relation between the back head and the cylinder to regulate the clearance between the rotor and the inner surface of the cylinder is obtained. The nut 50 is then tightened, thereby xing the adjusting the device rmly to the back head, so that further dis-assembly and assembly of the pump will not disturb the relationship selected between the barrel and the back head of the pump.

By similar means, the mounting head 24 of the pump is adjusted Awith relation to the barrel I2.

The flanges i4 and I8 and I6 and 20 are then secured respectively together by a quantity of bolts, not shown here, the holes for which are slightly over-sized to permit the adjusting movement provided by the dowel pins.

There is thus provided an adjustable dowel pin adapted to vary the alignment between mating surfaces and affording means for selecting and maintaining a desired relationship between said surfaces, which will be positive and reliable in use, easy to manufacture and install, and which will obviate the necessity for time-consuming and problematical trial-and-error methods of assembling such units as, for example, a pump.

Although only one embodiment and one application of the invention have been illustrated and described, other changes and modications in the form and relative arrangement of parts, which will be apparent to those skilled in the art, may be made without departing from the spirit and scope of the invention.

What is claimed is:

1. In a pump including a barrel member, an end member adjustably and releasably secured to said barrel member, and a rotor rotatably supported in said end member and positioned within said barrel member, the combination with said barrel and end members of means for adjusting one relative to the other to thereby adjust said rotor relative to said barrel membensaid means comprising a dowel pin having a cylindrical portion and a tapered portion coextensive therewith, one of said members having a cylindrical seat formed therein to receive the cylindrical portion of said dowel pin, the other of said members having a tapered seat formed therein to receive the tapered section of said dowel pin, the center lines of the cylindrical and tapered portions of said dowel pin being offset relative to each other, whereby said dowel pin is effective upon rotation to adjust one of said members relative to the other to thereby adjust said rotor relative to said barrel member, and means for xedly securing the tapered portion of said dowel pin to said one member whereby said members may be disassembled and reassembled without eiecting the relative position of said barrel member to said rotor.

2. In a pump including a barrel member, an end member adjustably and releasably secured to said barrel member, and a rotor rotatably sup- Y lindrical seat formed therein to receive the cylindrical portion of said dowel pin, said end member having a tapered seat formed therein to receive the tapered portion of said dowel pin, the center lines of the cylindrical and tapered portions of said dowel pin being offset relative to each other, whereby said vdowel pin is effective upon' rotation to adjust said end member relative toA said barrel member to thereby adjust said rotor relative to said barrel member, and means for xedly securing the tapered portion of said dowel pin to said end member whereby said barrel and end members may be disassembled and reassembled without eiecting the relative position of said barrel member to said rotor.

3. In a pump including a barrel member, an end member adjustably and releasably secured to said barrel member, and a rotor rotatably supported in said end member and positioned within said barrel member, the combination with said barrel and end members of means for adjusting the latter relative to the former to thereby adjust said rotor relative to said barrel member, said means comprising a cylindrical seat formed in said barrel member, a tapered seat formed in and extending through said end member, the base of said tapered seat facing said cylindrical seat, a dowel pin having a cylindrical portion slidably engaged with said cylindrical seat and a tapered portion coextensive with said cylindrical portion and engaged with said tapered seat, a threaded head on said tapered portion extending through said end member including means for turning said dowel pin, the center lines of said` cylindrical and tapered portions being offset whereby turning said dowel pin adjusts said end member relative to said barrel member to thereby adjust the position of said rotor relative to said barrel member, and a nut engaging said threaded head and bearing against said end member whereby said tapered portion is drawn into xed engagement with its coacting seat to thereby secure said dowel pin to said end mem' ber in fixed relationship thereto and whereby said barrel and end members may be disassembled and reassembled without affecting the relative position of said barrel member to said rotor.

ARTHUR H. LE FEBVRE. DAVID E. D. SMITH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 885,783 Palmer Apr. 28, 1908 1,767,019 Sergee June 24, 1930 2,037,894 Grisell Apr. 21, 1936 2,135,760 Moore Nov. 8, 1938 2,489,931 Rodaway Nov. 29, 1949 

